Comparative antifungal activity of plant- and microbe-mediated silver nanoparticles against Fusarium oxysporum f. sp. cubense

Fusarium oxysporum f. sp. cubense , the causal agent of banana wilt, is a destructive soil-borne pathogen. Because no chemical treatment can eliminate F. oxysporum f. sp. cubense once it becomes established in soil, control relies on prevention, hygiene, and containment, underscoring the need for complementary, sustainable suppression tools. In this work, silver nanoparticles (AgNPs) were synthesized via two eco-friendly routes: a plant-mediated method using Psidium guayaquilensis leaf extract and a microbe-mediated method using extracellular filtrate from Trichoderma spp. isolates; and their in vitro antifungal activity was compared against four F. oxysporum f. sp. cubense race 1 isolates. UV–Vis spectroscopy was used to guide synthesis parameter selection (AgNO₃ concentration, extract fraction, pH, time, temperature), and both preparations exhibited LSPR bands consistent with AgNP formation, with route-specific trends. FTIR FTIR identified organic functional groups associated with the respective biological matrices, and TEM revealed route-dependent morphology and particle-size distributions, with microbe-mediated AgNPs exhibiting a smaller characteristic ECD than plant-mediated AgNPs. Antifungal activity was evaluated in 96-well microdilution (24 h, 28 °C), revealing concentration-dependent inhibition for both nanoparticle types. Notably, microbe-mediated AgNPs consistently outperformed the plant-mediated counterpart, achieving lower IC 50 values across strains (≈ 22.18–27.87 mg L − 1 for microbe-mediated vs. ≈47.78–67.10 mg L −1 for plant-mediated AgNPs), with complete or near-complete growth suppression at the highest dose tested. These findings indicate that the synthesis route was associated with differences in nanoparticle characteristics and antifungal performance. Overall, microbe-mediated AgNPs emerge as a promising, sustainable candidate for F. oxysporum f. sp. cubense suppression, while the comparative framework presented here provides practical guidance for tailoring biogenic nanomaterials for plant disease management.